//The MIT License

//Copyright (c) 2009 Lluis Sanchez, Nick Darnell

//Permission is hereby granted, free of charge, to any person obtaining a copy
//of this software and associated documentation files (the "Software"), to deal
//in the Software without restriction, including without limitation the rights
//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//copies of the Software, and to permit persons to whom the Software is
//furnished to do so, subject to the following conditions:

//The above copyright notice and this permission notice shall be included in
//all copies or substantial portions of the Software.

//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//THE SOFTWARE.

using System;
using System.Reflection.Emit;

namespace Polymorph
{
    public class CodeAnd : CodeConditionExpression
    {
        private CodeExpression m_exp1;
        private CodeExpression m_exp2;

        public CodeAnd(CodeExpression exp1, CodeExpression exp2)
        {
            m_exp1 = exp1;
            m_exp2 = exp2;

            if (exp1.ResultType != typeof(bool))
                throw new ArgumentException("Operator 'And' can only be applied to operands of type 'bool'", "exp1");

            if (exp2.ResultType != typeof(bool))
                throw new ArgumentException("Operator 'And' can only be applied to operands of type 'bool'", "exp2");
        }

        public override void Generate(ILGenerator gen)
        {
            Label falseLabel = gen.DefineLabel();
            Label endLabel = gen.DefineLabel();

            if (m_exp1 is CodeConditionExpression)
                ((CodeConditionExpression)m_exp1).GenerateForBranch(gen, falseLabel, false);
            else
            {
                m_exp1.Generate(gen);
                gen.Emit(OpCodes.Brfalse, falseLabel);
            }

            m_exp2.Generate(gen);
            gen.Emit(OpCodes.Br, endLabel);
            gen.MarkLabel(falseLabel);
            gen.Emit(OpCodes.Ldc_I4_0);
            gen.MarkLabel(endLabel);
        }

        public override void GenerateForBranch(ILGenerator gen, Label label, bool branchCase)
        {
            Label endLabel = gen.DefineLabel();
            m_exp1.Generate(gen);

            if (m_exp1 is CodeConditionExpression)
            {
                if (branchCase)
                    ((CodeConditionExpression)m_exp1).GenerateForBranch(gen, endLabel, false);
                else
                    ((CodeConditionExpression)m_exp1).GenerateForBranch(gen, label, false);
            }
            else
            {
                m_exp1.Generate(gen);
                if (branchCase)
                    gen.Emit(OpCodes.Brfalse, endLabel);
                else
                    gen.Emit(OpCodes.Brfalse, label);
            }

            if (m_exp2 is CodeConditionExpression)
            {
                if (branchCase)
                    ((CodeConditionExpression)m_exp2).GenerateForBranch(gen, label, true);
                else
                    ((CodeConditionExpression)m_exp2).GenerateForBranch(gen, label, false);
            }
            else
            {
                m_exp2.Generate(gen);
                if (branchCase)
                    gen.Emit(OpCodes.Brtrue, label);
                else
                    gen.Emit(OpCodes.Brfalse, label);
            }

            gen.MarkLabel(endLabel);
        }

        public override void PrintCode(CodeWriter cp)
        {
            m_exp1.PrintCode(cp);
            cp.Write(" && ");
            m_exp2.PrintCode(cp);
        }

        public override Type ResultType
        {
            get { return typeof(bool); }
        }
    }
}